An acclaimed academic and author, he is a professor of photography at the Rhode Island School of Design, the same place where as a student he learned at the developer-stained knees of Aaron Siskind and Harry Callahan.

At age 56, he has authored several acclaimed textbooks on the history and the (often arcane) techniques of photography.

He also has authored children's books.

Too, Henry appreciates the track with a horseplayer's sense of what it takes to cross the finish line a winner. (Recently, in the wake of Funny Cide's upset win at the Kentucky Derby, I asked Horenstein about the then-upcoming Preakness. "I think Funny Cide's the real thing," Horenstein said. And damned if the horse didn't go on to win the Preakness in a walk. (Well, not really a walk, but you know what I mean.)

These are a lot of fields to be good in: from academia to the racetrack. And it's a rare bird indeed who can succeed in all of them

But I'm forgetting the most important one.

Henry Horenstein also is a hell of a photographer.

My first encounter with Horenstein's work was in his gorgeous, evocative book, Racing Days, a black and white encomium to the turf science that seemed to combine Damon Runyon with Walker Evans. Then came Baseball Days (and the hope that he was not going to continue with that title gimmick.) This one was all in color and even if it were not as strong in impact as its predecessor, it did combine a clear love of the game with some remarkably off-the-wall images one does not usually find in the boringly predictable coffee table tributes to the national sport. (One reason for this was that Horenstein did not just ply big league ballparks waiting for great moments in good light. He shot in places from Caracas, Venezuela to the Montana State Prison. Even at The Show he made wonderfully unusual pictures: then Red Sox ace Roger Clemens, on the mound but on one knee, pitching underhand during a Father and Son/Daughter game at Fenway.)

But the last decade has seen Horenstein move decidedly inward, and return to his black and white roots  while exploring the familiar yet strange contours of the animal world. Aquatics (Stewart, Tabori and Chang, $35), the latest book in this series, may be Horenstein's best. It certainly is the most coherent and unified-and perhaps the most determinedly artistic of a series of books on critters that have included several clearly (albeit affectionately) aimed at the mass market.

Images from Aquatics-now on view through June 21 at the newly renovated Kathleen Ewing Gallery on Connecticut Avenue-have been translated into lush, warm-toned platinum prints that help preserve the underwater-ness of the world Horenstein captured. Some images, like a detail of brain coral, or the delicately veined tail of a beluga whale, or the tentacles of a giant pacific octopus, are consciously made abstracts that combine artistic sense with wonder at things rarely seen so close-up.

Other images, like those of an inquisitive harbor seal or of a strangely engaging gold dust newt or longnose skate, hold our attention because they seem to be talking to us, or at least studying us through the glass.

Glass? Well, yes. One thing that I find refreshing, if not reassuring, about this work is that Horenstein did not travel the world in a wet suit and with a Nikonos to make these wonderful pictures underwater. "I'm not that brave," he told me.

Instead, he traveled the world during a sabbatical year from RISD to visit aquariums, armed only with a "very simple" rig: A Canon EOS 1v with several different lenses, "but mostly a 100mm macro and 50mm f.1..."

This is what gets me about this work. That it hangs together so well is not surprising-the photographs are uniformly excellent. But that Horenstein was able to make what sometimes appear to be studio-lit underwater images while, essentially, being a camera-toting tourist walking in off the street to, say, the Baltimore Museum, is just short of astonishing.

It puts the lie to the "if only" school of photography. ("If only I had a better camera, [or really cool lighting gear, or whatever] I'd take great pictures too.")

"The tough part was waiting and being patient," Horenstein said. "[Waiting] for the subjects-the fish-as you can't direct them. And also for the crowds. There were lots of people, school groups, etc., that I had to work around. (worm around?)"

"I usually just put my lens flat against the glass. Or look[ed] for an exhibit that has glass facing a dark wall-no reflections. Lots of aquariums are built that way to make viewing the exhibitions easier."

[In discussing this bit of technique, I added one of my own. When shooting an object behind glass or in a vitrine, I sometimes would rely on a rubber lens shade, and place that-not the lens itself  against the case. This can avoid the possibility of scratches, and also provide a fraction more mobility when shooting.]

While maintaining that his aversion to actually going into the water to make pictures is based on, well, aversion, Horenstein also makes a good case aesthetically. "Underwater you would need flash and the light would be flatter [not to mention occasionally harsher] And you can't isolate the subjects as well as you can in an aquarium. I wanted to shoot them as though they were in a studio: plain backgrounds, beautiful light."

Then there is the perennial question (to some anyway): why black and white?

"Black and white is more abstract and timeless to me. Less documentary in that it is less about the specific animal and more about a beautiful/mysterious form. More metaphoric and less descriptive."

Certainly, that is at work here in these gentle, beautiful photographs. To paraphrase with apologies to author Kazuo Ishiguro, Henry Horenstein is an artist of a floating world.

Aquatics-Photographs by Henry Horenstein. Through June 21. Kathleen Ewing Gallery, 1609 Connecticut Avenue NW (along with work by Anderson and Low: Gymnasts) Wed-Fri, 12-5 and by appointment. 202-328-0955. www.kathleenewinggallery.com

Frank Van Riper is a Washington-based commercial and documentary photographer and author. His latest book is Talking Photography (Allworth Press), a collection of his Washington Post columns and other photography writing over the past decade. He can be reached through his website www.GVRphoto.com.